Fig. 9.

Natural history of the Math5 lineage. (A) The timing of Math5 expression shifts during retinal histogenesis. RPCs (white) shift from a proliferative (P-P) mode of division to stem (N-P) or terminal (N-N) modes, giving rise to neurogenic cells (gray). These express Math5 (red) either during (S, symmetric) or after (A, asymmetric) final mitosis. During early retinal development (<E14), Math5 is frequently expressed during G2 phase of the last cell cycle, generating two Math5+ daughters. During later stages (>E15), Math5 is exclusively expressed by post-mitotic cells. (B) The size of the neurogenic (birthdated) population and proportion of Math5+ cells changes during development. At the onset of neurogenesis (E11), Math5 is expressed by 20-30% of newborn cells. The number of Math5+ cells peaks during midgestation (E14) and rapidly diminishes (E16), while the neurogenic population as a whole continues to expand. The temporal profile for RGC birthdates follows similar kinetics, and reflects Math5+ and Math5 populations. (C) The fate spectrum of Math5 lineage (red) and other neurogenic (gray) cells in wild-type and mutant mice. The thickness and shading of arrows denotes the relative demographic contribution of these cohorts to the mature retina.